some novel studies of thermodynamics, kinetics and transport phenomena in slags

DOI 10.1515/htmp-2012-0067 High Temperature Materials and Processes 2012; aop

Luckman Muhmood, Anna Semykina*, Masanori Iwase and Seshadri Seetharaman

Some Novel Studies of Thermodynamics, Kinetics and Transport Phenomena in Slags

Abstract: The following paper revolves around the research work conducted in collaboration during his brief visits to the Materials Process Science Division at Royal Institute of Technology, Stockholm. The paper focuses on the thermodynamic aspects of CaO–FeO–SiO2 and CaO–FeO–SiO2–MnO slag oxidation in air and sulfur transport through CaO–Al2O3–SiO2 slag. The thermodynamics of slag oxidation in air opens potential new areas in terms of focus on effective recovery of iron oxide from the slag. The slag transport studies are of fundamental nature and focuses on a novel technique to calculate the diffusion of species through slag by analyzing its corresponding con-centration in the metal phase.

Keywords: slag, thermodynamics, kinetics, transport phe-nomena, sulfur diffusivity, slag utilization

PACS® (2010). 05.70.-a, 72.15.-v, 72.25Ba

Luckman Muhmood: Royal Institute of Technology, Division of Materials Process Science, SE-100 44, Stockholm, Sweden. Currently with CSIRO Process Science and Engineering, Melbourne, Australia*Corresponding author: Anna Semykina: Royal Institute of Technology, Division of Materials Process Science, SE-100 44, Stockholm, Sweden/National Metallurgical Academy of Ukraine, Dnipropetrovsk, 49600, Ukraine, E-mail: [email protected] Iwase: Late Professor Iwase was at Kyoto University, Kyoto, JapanSeshadri Seetharaman: Royal Institute of Technology, Division of Materials Process Science, SE-100 44, Stockholm, Sweden. Currently visiting professor at TU Bergakademie Freiberg, Freiberg, Germany

1 IntroductionThermodynamics is a very powerful area of science which mainly focuses on the calculation of complex chemical and metallurgical equilibrium reactions, signifying the conditions which favour as well as oppose it. This helps in planning well ahead before conducting actual experi-ments. In terms of slags, where the typical composition would consist of at least 3–4 oxides, it simplifies time-

consuming experimentation. The introduction of sophis-ticated and dedicated software like Thermocalc and FactSage has made planning easier, again adding knowl-edge of both the scientist and engineer. However in-depth understanding of the fundamentals behind the process could only be obtained by experimentation. Kinetics, on the other hand, focuses on the reaction rates and mecha-nisms. Together with mass transport studies that includes diffusion, the knowledge of the kinetics and thermody-namics helps in understanding and predicting the mecha-nisms of process metallurgy reactions in best possible way.

The current paper is divided in two parts; the first part focuses on the thermodynamics and kinetics of the oxida-tion of iron oxide in iron-bearing slags (with iron oxide concentration 25–30 mass%). It pin-points the importance of thermodynamics in unveiling a more sustainable approach to recover iron from the metallurgical waste slags, hence improving the recovery of valuable material as well as enhancing the recycling potential of the slag thus obtained. The whole concept revolves around the oxidation of non-magnetic wüstite to magnetite, thereby increasing the iron recovery by magnetic separation. The proof of concept is done by thermodynamic analyses as well as using thermogravimetric technique (TGA). The kinetics of the oxidation of Fe2+ to Fe3+ is rigorously studied and the possible rate controlling steps have been put forward.

In the second part, a novel technique to measure the chemical diffusivity of species in slag is dealt with. The novelty of this technique is that the diffusivity of the species in the slag phase can be determined from its con-centration profile in the metal phase. The same can be achieved by specially designed experiments and a model which incorporates all experimental physicochemical property data of the slag/metal involved. The methodol-ogy is validated by experiments designed to measure the diffusivity of sulfur in slag.

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2 L. Muhmood et al., Some Novel Studies of Thermodynamics, Kinetics and Transport Phenomena in Slags

2 Thermodynamic analyses of liquid CaO-FeO-SiO2 and CaO-FeO-SiO2-MnO slag oxidation in air

The current scenario of depleting source of rich ores burdens the metal industry worldwide to find alternate methods/process which could incorporate lean ores. A fully sustainable utilization of waste steel slag should focus the recovery of valuable materials (iron in this context, apart from other valuable metals) at the same time improve the recycling potential of the remaining slag. An approach to utilize steelmaking slag components based on transformation of non-magnetic iron monoxide to magnetite by oxidation has been proposed earlier [1]. Air can be used to produce an oxidizing atmosphere, which would allow selective oxidation of iron in the slag. To analyse the feasibility, the thermodynamic calculations were performed.

The phase equilibria for the binary, ternary and quaternary slag systems containing iron oxide have been studied by several authors [2–4]. The majority of the exist-ing phase diagrams containing CaO, FeO, SiO2, and MnO are constructed to be valid at low oxygen partial pres-sures. The current work investigates the oxidation path of liquid CaO-FeO-SiO2 and CaO-FeO-SiO2-MnO slag systems in air.

During the oxidation of molten CaO-FeO-SiO2 and CaO-FeO-SiO2-MnO slags in an environment oxidizing enough to increase the valence of Fe, the following reac-tions may take place:

3(FeO)slag + 1/2O2 = (Fe3O4)solid (1)

2(FeO)slag + 1/2O2 = (Fe2O3)solid (2)

2(FeO)slag + (MnO)slag + 1/2O2 = (MnFe2O4)solid (3)

The final products after oxidation are magnetite and man-ganese ferrite, which can be separated by magnetic sepa-ration for further utilization.

In this work, FeO is considered stoichiometric. In order to find out the possible phases that could be obtained in air, thermodynamic calculations were per-formed by using FactSage 6.1 ((Thermfact Ltd. (Montreal, Canada) and GTT Technologies (Aachen, Germany)). Figure 1 represent phase diagrams (temperature vs. partial pressure of oxygen) of the ternary system 37.5 mass% CaO, 25 mass% FeO, 37.5 mass% SiO2 and quaternary system 27.5 mass% CaO, 30 mass% FeO, 15 mass% MnO, 27.5 mass% SiO2, respectively.

It is seen in Figure 1(a) that, above approximately 1600 K, the slag occurs as a homogeneous liquid phase at the oxygen partial pressure equal to that corresponding to air. As the system is cooled to temperatures below 1550 K and log10(p(O2)) around 2, magnetite precipitates along with CaSiO3, while at higher oxygen pressures, hematite is formed along with CaSiO3. For this system, to produce magnetite, it is advantageous to use a lower partial pres-sure of oxygen rather than in air (e.g., CO2 gas or CO2/air mixture). However it is important to emphasize that the industrial slags are multicomponent systems. It would be interesting to analyse phase equilibria in the quaternary slag system.

Fig. 1: (a) The phase stability diagram of ternary 37.5 mass% CaO – 25 mass% FeO – 37.5 mass% SiO2 slag system, (b) The phase stability diagram of quaternary 27.5 mass% CaO – 30 mass% FeO – 27.5 mass% SiO2 – 15 mass% MnO slag system both calculated by FactSage 6.1. A line marked A corresponds to the partial pressure of oxygen in air. P(O2) presented in Pa.



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L. Muhmood et al., Some Novel Studies of Thermodynamics, Kinetics and Transport Phenomena in Slags 3

Figure 1(b) shows a phase stability diagram of the qua-ternary 27.5 mass% CaO, 30 mass% FeO, 27.5 mass% SiO2, 15 mass% MnO slag system. At the low partial pressure of oxygen (log10(PO2) = −5) and above 1430 K, the slag is com-pletely molten. With the introduction of the oxidant gas, viz. air, Fe2+ in the slag changes its valence and, depending upon the temperature, different phases are precipitated. It is seen in Figure 1(b) that, in air, in the temperature range of 1548–1607 K, only spinel may be thermodynamically obtained from the liquid slag due to oxidation.

For further thermodynamic and kinetic analyses, the ternary slag of composition 37.5 mass% CaO – 25 mass% FeO – 37.5 mass% SiO2 was taken. The slag was made from standard chemical powders of high purity, while the FeO was synthesized and analyzed for impurities in-house. The slag components were mixed to obtain the desired composition and loaded in the TGA unit for conducting the oxidation experiments. The details of the purity of the slag components used, slag preparation and experimental set-up have been mentioned earlier [5]. Prior to the exper-iments, the starvation rate of air flow through the furnace was determined and later used for all further experiments. The experimental temperatures were chosen such that the liquidus temperature of the slag was well below it.

2.1 Results and discussion

Typical experimental curves for the isothermal weight gain during oxidation at different temperatures are shown in Figure 2. In this figure, the horizontal lines indicate the theoretical levels corresponding to the complete oxidation of Fe2+ in the slag to Fe3+ (theoretically corresponding to hematite) and even the partial oxidation corresponding to magnetite stage. The characteristics of the curves demon-

strate that, during the first 10 to 15 minutes of the experi-ment, approximately 70–90% oxidation level was reached for the oxidation to hematite stage. Figure 2 shows that an increase in temperature between 1623 K and 1723 K is fol-lowed by the progressive mass gain caused by oxidation. The maximum oxidation level achieved also increases for all slags studied with a rise in temperature. However, at 1773 K, the oxidation behaviour is somewhat different; it proceeds rapidly in the early stage but slows down at the later stage. The final mass gain (i.e., oxidation level achieved) is below the corresponding levels at 1673 K and 1723 K. In order to study the reason behind this different behaviour during oxidation at 1773 K, the samples oxi-dised at 1773 K and 1673 K were cooled at the rate of 25 K/ min in the TGA furnace. These samples were later anal-ysed by X-ray Diffraction (XRD). The surface layer for the sample oxidised at 1773 K contained mostly magnetite (and some hematite), as shown in Figure 3(a). On the other

Fig. 2: The isothermal mass changes curves for the following composition: 25 mass% FeO – 37.5 mass% CaO – 37.5 mass% SiO2 for different temperatures.

Fig. 3: The XRD pattern of the top layer of the sample (25 mass% FeO – 37.5 mass% CaO – 37.5 mass% SiO2) at temperatures (a) 1773 K and (b) 1673 K. o = Fe2O3 (rhombohedra); ♦ = Fe3O4 (FCC); ∙ = CaSiO3; ▾ = Ca2Fe2O5.



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hand, XRD analysis of the sample, oxidized at 1673 K, shows a multiphase structure in the surface layer (Figure 3(b)). The found phases are in agreement with the FactSage 6.1 calculations shown in Figure 1(a).

The isothermal mass change curves show differ-ences in slopes at different stages of oxidation that indicate the change of mechanism as the reaction pro-gressed. Oxidation may take place by steps (see Figure 4), starting first with an incubation period (correspond-ing to the initial oxygen dissolution in the slag), then, the chemical reaction rate-controlling step (correspond-ing to a linear part of the slope), and finally, diffusion of iron/oxygen rate-controlling step (corresponding to the parabolic part of the slope). The region where the transition from chemical control to diffusion con-trol, is marked in the figure as ‘mixed control’. Further details on the different rate of reactions are mentioned in [5].

3 Sulfur transport studies through CaO–Al2O3–SiO2 slag

It is well known that the transport of species through gas media is very fast and also that the interactions at the interface are electrochemical in nature and are likely to take place rapidly [6] if the charge transfer is enabled suit-ably. Hence the rate-controlling step for the transport of any particular species in pyro-metallurgical process would be the transport through the metal and slag phases. It has been well-established that the diffusion coefficients of a species, as for example S in the metal phase is roughly two orders of magnitude higher than the corresponding species through slag [7]. Thus the rate-determining step in such reactions would be the diffusion through the slag phase. Hence, the estimation of diffusion coefficients in the slag phase is of extreme importance for a better control of such processes.

The diffusion coefficients of various species in slag media have been estimated mainly by using a suitable radioactive tracer. Other methods of estimation are by using the electrochemical method or diffusion couple method. Some of the elements investigated by earlier researchers along with the slag system details and mea-surement technique used is shown in the Table I. From this table, it can be seen that the chemical diffusivity has not been studied extensively in comparison to the other methods. The main reason could be due to experimental difficulties focused around slag quenching. It is practically difficult to freeze the slag effectively and hence during quenching, there could be small gradients resulting in a variation in the diffusivity obtained. Thus, a new method

Fig. 4: Illustration of the plausible steps in the oxidation mechanism marked on a typical isothermal mass change curve.

Element investigated Tracer used Slag system Method

Si Si31 CaO-SiO2 Capillary reservoir [8]Ca Ca45 CaO-SiO2 Capillary reservoir [9]Ca Ca45 CaO-Al2O3, CaO-Al2O3-SiO2 Instantaneous plane source/

Capillary reservoir [10]F F18 CaO-Al2O3-SiO2 Instantaneous plane source/

Capillary reservoir [10]Mn, Fe, Ca, Si – CaO-Al2O3-SiO2-MnO-FeOx Capillary reservoir [7]Fe Fe59 CaO-Al2O3-SiO2 Capillary reservoir [11]Al Al26 CaO-Al2O3-SiO2 Capillary reservoir [12]O O17,O18 CaO-Al2O3-SiO2 Capillary reservoir [13]Ca Ca45 CaO-Al2O3-SiO2 Diffusion couple [14]S S35 CaO-Al2O3-SiO2 Diffusion couple [15]S – CaO-Al2O3-SiO2 Chemical Diffusion [16]

Table I: Details of elements investigated along with the slag system used and diffusion method.



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for the in-situ measurement of sulfur content in the system has been focused upon. This measurement technique uses metal sampling for sulfur analysis without disturb-ing the slag-metal interface and hence reducing the after effects obtained during slag quenching.

A novel technique has been put forward for the evalu-ation of the chemical diffusivity of sulfur in the molten slag phase. A mathematical model [17] was formulated through which appropriate design parameters for the experimental setup was obtained. For this, the order of magnitude for the diffusion coefficient for sulfur was taken from the classic works of Saitô and Kawai [15], the sulfide capacity and sulfur partition ratio were retrieved from the works of Taniguchi et al. [18], and the slag density was retrieved from earlier experimental results of the present authors [19]. The Henrian activity coefficients for the metallic solution were also retrieved from literature [20]. Using the model and experiments, the chemical diffusion coefficient values of sulfur in the ternary slag of composition 51.5 mass% CaO- 9.6 mass% SiO2- 38.9 mass% Al2O3 slag was measured at 1680, 1700 and 1723 K [21].

3.1 Realization of experiments

The physical translation of the model to experiments is of immense importance for the success of the concept. Proper experimental planning in terms of the material of the crucible, the composition of the slag and metal, the source for sulfur, working temperature, sampling time and technique, etc. was addressed. The following sections explain the methodology used to tackle these hurdles.

Sulfur transport through different metal phases

The model was used to find out the sulfur movement through the same slag with identical conditions but differ-ent metal phases. The exercise was to estimate the effect of the solubility of sulfur in various metal phases and its effect on the sulfur transport in the slag phase. Iron and silver were used as the metal phases individually. The sol-ubility of sulfur in molten iron and silver could be calcu-lated [20]. It was found that, under identical conditions, the solubility of sulfur in molten iron was more than that in molten silver.

Figure 5 shows the sulfur transport in the slag phase with identical conditions but with different metal phases.

The right extreme in the figure represents the slag-metal interface. The higher sulfur concentration at the slag-metal interface in the case of silver is due to the lower sol-ubility of sulfur in molten silver in comparison to molten iron.

The ultimate driving force for the movement of sulfur from the gas phase to the liquid metal would be the chem-ical potential difference of sulfur between the gas and the metal phases. In case of iron, the potential is much higher owing to the higher solubility of sulfur in iron. Despite this, there is no significant variation in the sulfur trans-port through slag. Thus it could be concluded that the thermodynamic relationships between the metal phase and sulfur do not have a significant impact on the sulfur movement in the slag.

Sampling technique and crucible design

The diffusivity of sulfur in slag depends on the slag com-position. However, the analysis of the slag in comparison to the metal involves larger errors due to unreliable mea-surement techniques. Hence it was decided to analyze the metal sample instead of slag. The problem of taking out metal samples without slag inclusion posed another difficulty. In order to overcome this, a special crucible structure was designed as shown in Figure 6. Based on the shape complexity and reaction with slag at high tempera-tures, it was decided to use pure Armco iron as the cruci-ble material along with stringent control of oxygen partial pressures. Accordingly, silver was chosen as the metal phase since its melting point was lower than that of iron and its negligible solubility with respect to iron. The upper limit for the experimental temperature was determined by the melting point of iron while the lower limit was decided by the melting point of the slag used.

Fig. 5: Sulfur concentration variation in the slag phase when using silver and iron metal phases independently [21]. The right extreme represents the slag-metal interface.



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Slag composition and working temperatures

After selecting the material for the crucible and metal phase, the next step was to find a suitable slag composi-tion that would give a reasonable working temperature. Further, a knowledge regarding the various slag proper-ties was required especially density. Since the authors had carried out density measurements in the low silica CaO-Al2O3-SiO2 ternary slag system [19], a slag of composition CaO = 51.5 mass%, Al2O3 = 38.9 mass% and SiO2 = 9.6 mass% was chosen. This gave a reasonable working tem-perature between 1673 K and 1723 K.

Source for sulfur

Probably the most difficult task of all was to select a suit-able source for sulfur. Since pure iron was used as the cru-cible material, the partial pressures of oxygen and sulfur had to be accurately controlled in order to prevent any formation of FeO and FeS. The desired values of pO2 and pS2 were 10−7 and 10−1 Pa respectively. After in-depth analysis of different alternatives, it was decided to use CaS pellets as the source of sulfur.

3.2 Results and discussion

The experimental set up and methodology are discussed in detail elsewhere [21]. Metal samples were taken at

regular intervals and these samples were then analyzed for sulfur. The concentration profile of sulfur in silver metal obtained by sampling was compared with that obtained by the model under the assumption of uniform composition. To calculate the diffusion coefficient of sulfur, the model was used [17]. In the model, the only term assumed was the diffusion coefficient; hence fitting the concentration curve to the experimental concentra-tion profile would help in back-calculating the diffusion coefficient. Table II shows the values of the diffusion coefficients at 1680, 1700 and 1723 K, by comparison of the model and experimental concentration profiles of sulfur.

The values for the diffusion coefficient of sulfur in the slag were found to be in good agreement with the trend of the values obtained by Saitô and Kawai [15] and with that of Derge et al. [16]. The slag used in the current work was below the orthosilicate region while that used by Saito and Kawai had more than 33 mass% silica content. Derge et al. used a quaternary slag composition 45.3 mass% CaO – 14.1 mass% Al2O3 – 37.1 mass% SiO2 – 3.5 mass% MgO and the diffusion coefficient of sulfur in slag varied from 9 × 10−7–6 × 10−6 cm2/sec.

The compositions of the slags used in the current work and that used in the classic works of Saitô and Kawai are compared in Table III. Other thermophysical proper-ties are also been compared. The values for the sulfide capacity have been obtained from the works of Taniguchi et al. [18]. The viscosities are taken from the classic works of Kozakevitch [22].

As seen from the table, the slag used by Saitô and Kawai had a lower sulfide capacity, which resulted in a lower sulfur diffusivity in the slag media. Further, the basicity of the slag was lower compared to the slag used in the current work. The viscosity of the slag used in the current work was higher in comparison to that used by Saitô and Kawai; however the higher sulfide capacity would lead to a higher value of diffusivity.

The effect of silica content present in the slag also affects the diffusivity. In the current slag compositions studied, the mole percent of SiO2 was well-below 33% required for the orthosilicate composition. This would

Fig. 6: Crucible design for experiment [21].

Temperature (K) Diffusion Coefficient × 106 (cm2.s−1)

1680 3.98 1700 4.041723 4.14

Table II: Diffusion coefficients of sulfur through 51.5 mass% CaO – 38.9 mass% Al2O3 – 9.6 mass% SiO2 slag.



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correspond to the existence of discrete SiO44− tetrahedral

units along with O2− in the silicate melt and thus ruling out the possibility of the impact of silicate polymerization. In the absence of polymerization, the melt system would consist of Ca2+, AlO4

−5, SiO44− and O2− ions, which would

result in a fast sulfur movement through the slag and thus a higher diffusion coefficient. It is also well known that the tracer, chemical and impurity diffusion coefficients decrease with increasing SiO2 content in the slag.

4 Conclusion

The thermodynamic analyses of liquid CaO-FeO-SiO2 and CaO-FeO-SiO2-MnO slag oxidation in air were performed by using FactSage 6.1 software. The oxidation of FeO in steelmaking slags (i.e., the oxidation of Fe2+ to Fe3+) has been investigated by TGA in synthetic slags in the ternary system CaO-FeO-SiO2. The TGA experiments showed that, during the first 10 to 15 minutes, 70 to 90% of oxidation was achieved. An increase of the temperature in the range 1623 K to 1723 K caused an increase in the rate of the reac-tion. The thermograms for oxidation showed an initial incubation followed by a chemical-reaction-controlled stage. At later stages, the reaction rate most likely was controlled by diffusion. The study could open a new per-spective in the future for an effective and sustainable post-treatment of slag. Sulfur transport through low silica CaO-Al2O3-SiO2 slag has been measured. This was carried out with combined application of modelling and experi-ments. The methodology could be used for other species like P, O etc. The order of the diffusion coefficient of sulfur in 51.5 mass% CaO- 9.6 mass% SiO2- 38.9 mass% Al2O3 slag was estimated to be 10−6 cm2/sec which is in good agree-ment with the results available in literature. The combina-tion of thermodynamics, kinetics and mass- transfer of species through slag can help in deep understanding of various phenomena in pyro-metallurgical operations.

AcknowledgementsThe authors are thankful to the Swedish Foundation for Strategic Environmental Research (MISTRA) and the Swedish Research Council (Project No: H 6971) for the financial support through the project Eco-Steel Produc-tion (Sub project no.: 88035), administered by the Swedish Steel Producers Association (Jernkontoret). Prof. N.N. Viswanathan is gratefully acknowledged for his immense help during developing the model. Dr. L. Teng is also acknowledged for very useful discussions.

Received: April 20, 2012. Accepted: July 6, 2012.

References[1] A. Semykina, V. Shatokha and S. Seetharaman: patent “Method

to utilise metallurgical slags”, No. 88122. С22В 7/04, С22В 9/05; 10.09.2009 (Ukraine).

[2] E.T. Turkdogan, Fundamentals of Steelmaking, The Institute of Materials, Cambridge, UK, (1996).

[3] C. Bodsworth and H.B. Bell, Physical Chemistry of Iron and Steel Manufacture, Longman, London, (1972).

[4] A. Muan and E.F. Osborn, Phase Equilibria among Oxides in Steelmaking, Addison-Wesley Publishing Company, Reading, MA, (1965).

[5] A. Semykina, V. Shatokha, M. Iwase and S. Seetharaman: Met. and Mat. Trans. B, 41 B, 1230–1239 (2010).

[6] F.D. Richardson: Physical Chemistry of Melts in Metallurgy, vol. 2, Academic press, (1974).

[7] M.D. Dolan and R.F. Johnston: Met. and Mat. Trans. B, 35 B, 675–684 (2004).

[8] H. Keller and K. Schwerdtfeger: Met. and Mat. Trans. B, 10 B, 551–554 (1979).

[9] H. Keller, K. Schwerdtfeger and K. Hennesen : Met. and Mat. Trans. B, 10 B, 67–70 (1979).

[10] R.F. Johnston, R.A. Stark and J. Taylor: Ironmaking and Steelmaking (Quarterly), 4, 220–227 (1974).

[11] D.P. Agarwal and D.R. Gaskell: Met. and Mat. Trans. B, 6 B, 263–267 (1975).

[12] J. Henderson, L. Yang and G. Derge: Trans. AIME, 221, 56–60 (1961).

Slag used by Saitô and Kawai Slag for current work

Composition (mass%)CaO 50.3 51.5Al2O3 10.4 38.9SiO2 39.3 9.6Diffusion Coefficient of sulfur (cm2/sec) 0.89 × 10−6 (at 1718 K) 4.14 × 10−6 (at 1723 K)Sulfide Capacity 0.49 × 10−4 0.447 × 10−3

Viscosity (Pa.s) 0.530 0.77

Table III: Comparison between the slags used by Saito and Kawai [15] and the current work.



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[13] P. Koros and T.B. King: Trans. AIME, 224, 299–306 (1962).[14] H. Towers, M. Paris and J. Chipman: Trans. AIME, 197,

1455–1458 (1953).[15] T. Saitô and Y. Kawai: Japan J. Inst. Metals, 17, 434 (1953).[16] G. Derge, W.O. Philbrook and K.M. Goldman: Trans. AIME, 188,

1111–1119 (1950).[17] L. Muhmood, N.N. Viswanathan and S. Seetharaman: Met. and

Mat. Trans. B, 42 B, 460–470 (2011).[18] Y. Taniguchi, L. Wang, N. Sano and S. Seetharaman: Met. and

Mat. Trans. B, Available online, 2012, DOI: 10.1007/s11663-011-9621-3.

[19] L. Muhmood and S. Seetharaman: Met. and Mat. Trans. B, 41 B, 833 (2010).

[20] O. Kubaschewski and C.B. Alcock. Metallurgical Thermochemistry, 5th Edition, Pergamon press, 47 (1979).

[21] L. Muhmood, N.N. Viswanathan, M. Iwase and S. Seetharaman: Met. and Mat. Trans. B, 42 B, 274 (2011).

[22] P. Kozakevitch: Rev. Metallurg., 57, 149 (1960).


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some novel studies of thermodynamics, kinetics and transport phenomena in slags

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